But who is liable?
One unanswered question about this (or about autonomous vehicles in general) is who is liable for any incidents? Limiting this to the US (as this is a US company talking about doing trials in the US), will the truck maker be liable in the event of accidents? The truck operator?
As Tesla's Autopilot has shown, even highway driving has edge-cases. A fire engine (or police car) may be stopped in your lane, and not visible until the vehicle in front swerves at the last minute. The road-markings may be worn or obscured. The sensors may be fooled.
For haulage vehicles, the question of the load also arises. Who is responsible for loading it safely, and securing the load? Who is liable if it shifts, or falls off onto the highway? At the end of the highway, the autotruck pulls off, and a human driver arrives. Must he re-inspect the load (and assume liability) before moving off?
With a driver, the law is clear: the driver is liable. Would a vehicle manufacturer really risk assuming that liability? The US courts have made it very clear that manufacturers can't just budget for some accidents (the Pinto case). So testing of software and hardware would need to be exceptionally rigorous, thorough and well-documented. "Move fast and break things" is unlikely to be acceptable as a development philosophy.
And if it does go to a court, expect all the documentation to be examined very thoroughly. "You can't see that, it's commercially valuable" is unlikely to hold up.
Would you invest in a company with that level of risk?